.container{
    width: 400px;
    height: 500px;
    border: 1px solid #000;
    margin: 0 auto;
    overflow-y: scroll;
    position: relative;
}
ul {
    list-style: none;
    margin: 0;padding: 0;
}
li{
    height: 50px;
    border-bottom: 1px solid #aaa;
    box-sizing: border-box;
    text-align: center;
    line-height: 50px;
}
.list-phantom{
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
}
